differences between validity and reliability

Experts(in this case, math teachers), would have to evaluate the content validity by comparing the test to the learning objectives. of each question, analyzing whether each one covers the aspects that the test was designed to cover.Ī 4th grade math test would have high content validity if it covered all the skills taught in that grade. However, it can happen that your assessment method provides valid results at first, but its reliability turns out to be low because you cannot achieve consistency after using it again. Validity refers to the accuracy of a measure (whether the results really do represent what they are supposed to measure). In fact, there is a strong relation between both these parameters as they all are elements of quality. Assessing content validity is more systematic and relies on expert evaluation. Reliability and validity are both about how well a method measures something: Reliability refers to the consistency of a measure (whether the results can be reproduced under the same conditions). A measurement maybe valid but not reliable, or reliable but not valid. On the other hand, content validity evaluates how well a test represents all the aspects of a topic. Reliability and validity are independent of each other. When a test has strong face validity, anyone would agree that the test’s questions appear to measure what they are intended to measure.įor example, looking at a 4th grade math test consisting of problems in which students have to add and multiply, most people would agree that it has strong face validity (i.e., it looks like a math test). The difference is that face validity is subjective, and assesses content at surface level. Face validity and content validity are similar in that they both evaluate how suitable the content of a test is.

Differences between validity and reliability